Patterns of exogenous insulin requirement reflect insulin sensitivity changes in trauma.

INTRODUCTION: We investigated patterns of blood glucose and exogenous insulin requirement in the intensive care unit, and questioned whether they reflect fluctuations in insulin activity.

METHODS: Records for burn intensive care unit patients with 7 days of glucose control with insulin were reviewed. Hourly blood glucose and insulin dose were matched for time collected and analyzed with linear and cosine regression. Frequency analysis identified recurring patterns.

RESULTS: Diurnal patterns of blood glucose and insulin requirement were noted (insulin troughs = noon; insulin peaks = midnight; glucose troughs = 5 am; glucose peaks = 5 pm). Average insulin requirement increased at a constant linear rate (slope = .013, r2 = .57, P < or = .001).

CONCLUSIONS: Diurnal patterns in blood glucose and insulin requirement mirror those of healthy subjects and may reflect persistence of normal variability in insulin activity. The 5-hour offset in peaks and troughs is suggestive of complex interplay between insulin availability and receptor sensitivity. The insulin requirement to blood glucose ratio increased, evidence that insulin resistance progresses over time.